I vote for there is no either or, it is both. One - With so many political buttheads with no idea whatsoever on the subjects which matter, doing our airspace management on a knowledge of micrometer thought GoogleEarthie-like misbelief and no own piloting experience, they make flying without GPS more and more dangerous. So, No, in many airspace cage constructions flying without GPS moving map may almost be impossible, but not because of physics, but incompetence in definition. Two - Electronic brain extensions may fail and it is good airmenship to have a backup = the paper chart. But, due to cultural change, sustaining on your own is a fading art. I see young pilots totally incapable of orientation in 3D space and for them, loosing GPS is an emergency with call for help, not assistance as it may have been in the ol' days.